Rhetorical questions are often humorous and don’t require an answer.

‘If you set out to fail and then succeed have you failed or succeeded?’  Rhetorical questions are often used by speakers in presentations to get the audience to think – rhetorical questions are, by design, used to promote thought.

Politicians, lecturers, priests and others may use rhetorical questions when addressing large audiences to help keep attention.  ‘Who would not hope to stay healthy into old age?’, is not a question that requires an answer, but our brains are programmed to think about it thus keeping us more engaged with the speaker.